The cellular telephone industry has made phenomenal strides in commercial operations in the United States as well as the rest of the world. Growth in major metropolitan areas has far exceeded expectations and is rapidly outstripping system capacity. If this trend continues, the effects of this industry's growth will soon reach even the smallest markets. Innovative solutions are required to meet these increasing needs as well as to maintain high quality service and avoid rising prices.
One of the greatest challenges associated with the continuing development of portable cellular telephone units used in radiocommunication systems involves providing an adequate portable power supply which is as small as possible. A battery pack is typically the main power source for these, and other, portable electronic devices, e.g., cellular phones and portable computers. The portable nature of cellular phones is limited by the fact that their battery power will not last forever. After a period of time the batteries become discharged and the cellular phone must be plugged into a charger in order to recharge the battery. In order to achieve more battery power (longer battery life), typically the size of the battery cell must be increased. This presents a problem for cellular telephone designers due to the conflicts between a desire for longer talk time and standby for the phone (i.e., longer battery life) and the desire for smaller, lighter telephones.
Existing solutions for the problems of shortened talk time and standby have been limited to the development of high capacity batteries for cellular telephone units. These batteries suffer from the limitations of size and weight mentioned previously. The conflict between size and power is made worse by the development of next generation telephones which are becoming smaller and smaller. Other solutions involve the use of improved battery technologies that increase the charge per volume and charge per weight ratios of existing battery systems. However, these improvements have not been sufficient to keep up with the smaller sizes of cellular telephone units that are possible using existing components and technologies. Thus, in order to increase a cellular telephone's battery life while at the same time leaving the size and weight of the cellular telephone unchanged, recent improvements include incorporating an auxiliary battery within a belt holder for a cellular telephone unit. Even in this instance though, a separate multi-battery charger must be supplied in order to charge the auxiliary battery as well as the internal battery of the cellular telephone unit. The size and weight of the typical multi-battery charger, however, is not suitable for travel nor does it meet the portability requirements of today's on-the-move cellular telephone user.